1. Field of the Invention
The invention relates to the treatment of fabrics to enhance their resistance to soiling, and more particularly to a novel process of so treating garments in the course of a conventional industrial dry cleaning operation without modification of any part of such an operation.
2. The Prior Art
The business of rental and cleaning of industrial garments involves repeated cleanings of fabrics which are exposed, between such cleanings, to heavy soiling as, for example, by automobile oils and greases carrying carbon particles in suspension.
When the fabrics composing such garments were woven of natural fibers, staining from such sources could be removed by and agitation in a high-temperature water-detergent mixture.
With the advent of synthetic fabrics, however, and their wide adoption for use in industrial garments, especially work shirts, it became impracticable to remove such stains by such means because of the effect of high temperatures on the strength of polyesters and like synthetic fabrics, and dry cleaning of them became a necessity.
In conventional dry cleaning, garments usually are manually "spotted" to remove heavy soil from limited areas. They then are cleaned by agitation in a mixture of an organic solvent, detergent and water which is being continuously recycled and filtered to remove suspended insoluble material; a portion only of the mixture being distilled in the course of such recycling, to prevent excessive accumulation of contaminents. Finishes such as stain repellents may be applied during or following such cleaning and thereafter "set," as described, for example, in the U.S. Pat. of Eanzel No. 3,854,871 and other patents referred to therein.
The degree of soil encountered in the industrial garment rental and cleaning business, and the economic factors prevailing in that industry, render it uneconomical to clean such garments by such a conventional dry cleaning method. The removal of stains by manual "spotting" is obviously excessively costly. The amount of insoluble material carried into suspension is too great to permit its removal in a continuous filtering operation because a conventional filter would soon be clogged. The application of a stain repellent finish, while obviously desirable, has involved excessive material and labor costs and therefore has seldom if ever been used.
Therefore, in industrial dry cleaning, as distinguished from that just described, it has been the practice to agitate a batch of garments such as shirts in a solvent-detergent-water mixture in which (prior to addition of water to the mixture) another batch of such garments, previously so processed, has already been agitated. The twice-used solvent-detergent-water mixture is then distilled to recover the solvent. Following the first agitation described, the batch of garments is subjected to a second agitation in a fresh solvent-detergent mixture after which that mixture, with water added, is used once more for the agitation of a new batch of soiled garments and then distilled as has been described. After drying, by centrifugation, solvent aspiration, etc., the garments are passed on hangers through a dry-steam finishing tunnel in which the application of heat and agitation of the garments effects the removal of wrinkles.
The application of a stain repellent finish to garments in the course of such an industrial dry cleaning process has heretofore proven uneconomical because such a repellent, if mixed with the solvent-detergent-water mixture, would, except for the small amount coated onto the fabric, be lost during the distillation operation; or, if sprayed on the garments in a separate operation at the conclusion of the cleaning operation as taught in the prior art, would involve excessive time and labor costs.
It is the primary object of the present invention, therefore, to provide an industrial dry cleaning process of the character described including provision for the application and setting of a stain repellent finish to the cleaned garments without modifying any of the steps described or increasing the time required for the completing of the cleaning and drying operation.